A door jamb is a vertical frame that surrounds a door, providing support and a finished appearance. It consists of two side jambs, a head jamb, and a threshold. The side jambs are attached to the studs of the wall, while the head jamb is attached to the top of the side jambs. The threshold is installed at the bottom of the door jamb and provides a weather-tight seal.
Door jambs are an important part of any door installation, as they provide structural support and help to keep the door in place. They also help to seal the door against air and water infiltration, making them an essential part of any energy-efficient home. Historically, door jambs were made of wood, but today they are also available in a variety of other materials, including metal, fiberglass, and composite materials.